1. Field of the Invention
The present invention relates to hand tools of the type which are relatively non-conducting electrically, so that they can safely be used in applications where they may come into contact with sources of electrical power.
2. Description of the Prior Art
Various types of electrically insulating hand tools have been available for many years. Such tools typically have a standard metal shaft/blade which, in addition to being connected to a handle which is formed of electrically insulating material, such as wood or plastic, is also coated or covered with an insulating material. Such insulated tools work acceptably well as long as the insulating covering is intact and in good condition. But, if the insulation becomes damaged, such a tool may be dangerous if it comes into contact with a source of electrical power, the danger being the risk of electrical shock to the user or inadvertent shorting of electrical circuits with which the shank may come in contact. Therefore, such insulated tools are not recommended for use on live electrical wiring, contacts or the like.
Certain types of tools with elongated shanks of plastic material have been provided heretofore, but they have not been hand tools provided with a handle at one end.
U.S. Pat. No. 5,259,277, discloses an electrically insulating hand tool, with a shank formed of composite material and fixedly secured, as by a suitable adhesive, in an axial bore in one end of an associated handle, which is also formed of an electrically insulating material. This screwdriver works well in terms of electrical insulation, but the adhesive attachment of the shank to the handle has disadvantages, in terms of assembly steps and torque strength of the resultant product. Furthermore, the composite material of the tool shank, while affording excellent electrical insulation characteristics, must be produced through preform resin impregnation, which has certain disadvantages as compared to other types of molding.
It is a general object of the invention to provide an electrically insulating hand tool which avoids the disadvantages of prior hand tools, while affording additional structural and operating advantages.
An important feature of the invention is the provision of an electrically insulating hand tool which is of simple and economical construction, avoiding the use of adhesives.
Another feature of the invention is the provision of an electrically insulating hand tool of the type set forth, which provides improved torque strength.
Yet another feature of the invention is the provision of a hand tool of the type set forth, which can be formed by injection molding, while offering improved electrical insulation characteristics.
These and other features of the invention are attained by providing an insulating hand tool comprising: an insulating hand tool comprising: an elongated torque-transmitting shank formed of high-strength, injection-molded, electrically insulating material and having a handle end and a working end, a handle formed of electrically insulating material and carried by the handle end of the shank, and a working tip having a mounting portion fixed in the working end of the shank and a work-engaging portion projecting from the working end of the shank, the mounting portion including an anchor portion having angularly spaced flutes substantially filled with material of the shank.